1. Field of the Invention
The invention relates to an image forming device, in particular, an image forming device for receiving a document file and forming images of said document file, wherein said document file contains objects for displaying a part or all of the contents of each page of the document and being capable of lining up in the file regardless of the order of said contents displayed in said document.
2. Description of Related Art
A personal computer (“PC”) is capable of transmitting a document file stored in, for example, a hard disk to a printer via a network such as LAN.
In this case, the document file is transmitted after being converted into print data described in a printer-recognizable PDL (Page Description Language) such as PS (PostScript®).
On the other hand, PDF (Portable Document Format) files are widely used being distributed over the Internet as a type of document file that can be reproduced in the same style as the original document regardless of the types of the OS (Operating System) or application. A PDF file contains objects for displaying a part or all of the contents of each page of a document, wherein said objects can line up within the file not necessarily according to the order of the contents displayed in the document and the document structure can be analyzed by referring to the positional information of said object within the file, the information about which objects are used to display which contents of each page, and the like.
In the meanwhile, a PDF file may contain several hundreds of data. When such a large PDF file is converted into print data by a PC, the load on the PC can be enormous due to the reason that it takes a long time to convert, requires a complicated process, it takes a long time to transmit the data as the data size increases as a result of the conversion, etc. In order to lighten the PC's load, printers that are capable of directly printing a PDF file transmitted directly from a PC without the conversion (“PDF direct printing”) have been proposed.
However, since a PDF file contains objects for displaying the contents of each page lining up in the file regardless of the order of said contents displayed in a document and also the reference information of the objects' positions in the file is located at the end of the file, a printer cannot start printing until after the entire PDF file is received. Consequently, such a printer sometimes ends up being unable to print a PDF file as it cannot receive the entire file due to the limitation of its memory capacity (usable capacity or vacant capacity) in some cases.
In order to cope with this problem, devices that are capable of modifying and reconstituting the contents of a PDF file in order to display the data in the order of receipt without having to receive the entire PDF file have been proposed (U.S. Pat. No. 6,067,553).
However, in case of the abovementioned device, it still requires a complicated process for reconstituting a PDF file on the transmission side, such as a PC, prior to the file transfer. Therefore, the technology in the above device has a problem that it does not reduce the load on the PC compared to converting PDF files into print data described in PDL such as PS. Moreover, the abovementioned technology is basically a technology of displaying on display units so that it does not take much consideration in printing on printers.